Traffic and highway safety signs are in widespread use to advise motorists and others of temporary or emergency conditions along roadways. These safety signs usually are intended for relatively temporary use at particular locations where repair or rebuilding of the roadway is taking place, or where other nonpermanent traffic safety conditions arise. To that end, such signs preferably are portable instead of being permanently installed in the ground, so that highway maintenance personnel can easily relocate the signs as repaving or repair progresses along the highway, or as temporary traffic conditions otherwise change.
Highway safety signs intended for temporary use usually comprise a sign panel bearing an appropriate warning or safety message, and a separate stand for supporting and displaying message panel. The support stands usually are designed and constructed so that one person can readily move the stand from a truck to a particular site, and the stands often are partially collapsible or foldable for occupying less space when stored. Some stands have a number of individual ground-engaging legs which support the stand when in use, and which are foldable to reduce the overall area occupied by the stand when not in use. Examples of traffic safety sign stands and related signs are shown in U.S. Pat. Nos. 3,591,116 and 4,498,657.
Safety sign stands intended for highway use must be relatively sturdy to withstand the environment of use. The stand also should quickly and easily accept a particular sign, and should be capable of locking the sign to the stand without requiring manipulation of screws or other controls to secure the sign to the stand. Securing the sign to the stand reduces the likelihood that a sign will become detached and lost, or will present a traffic hazard if the stand becomes overturned by strong winds or by a vehicle striking the stand. However, the stand also should permit easy unlocking and removal of a previously-attached sign, preferably without bending over to release or unlatch the locking mechanism in the stand, so that a person can remain upright while unlocking the sign and lifting it from the stand. Further yet, a sign stand should accept and support, without special adapters or mounting masts, flexible signs having rigid corner brackets; such flexible signs are disclosed in U.S. Pat. No. 4,426,800.